It is known to make tert-amine oxides by the reaction of aqueous hydrogen peroxides with tert-amines. This reaction can also be conducted using a co-solvent such as a lower alcohol to prevent gel formation.
Murata et al. U.S. Pat. No. 4,247,480 discloses that the formation of amine oxides from tert-amine by reaction with hydrogen peroxide can be promoted by including 0.01-2 weight percent carbon dioxide based on the tert-amine. Murata et al. demonstrates the process at 55.degree.-65.degree. C. and obtains excellent yields of amine oxides.
It is known that nitrosamine impurities are routinely formed when reacting hydrogen peroxide with tert-amines. This would not be a problem if it were not for the fact that nitrosamines are suspected carcinogens and mutagens and even small amounts cannot be tolerated in products intended for contact with humans, "Nitrosamines: Assessing the Relative Risk" Chemical & Engineering News, pages 20-26, Mar. 31, 1980. The major uses for tert-amine oxides are in cosmetic and surfactant formulations including such things as laundry detergents, hair shampoo and hair conditioners, all of which come in contact with humans. This necessitates special procedures to remove nitrosamine impurities from tert-amine oxides before they can be used in their major marketing areas. Such treatments include the exposure of the tert-amine oxide to ultra-violet irradiation (anonymous GB RD 269056A). Therefore a need exists for a process for making tert-amine oxides that have low concentrations or are substantially free of nitrosamine impurities without resorting to any special purification procedure after the synthesis operation.